The share of total assets of all families attributable to unrealized capital gains from real estate, businesses, stocks, or mutual funds fell 11.6 percentage points to 24.5 percent in 2010, it said.

While the overall level of debt owed by families was unchanged, debt as a percentage of assets rose to 16.4 percent in 2010 from 14.8 percent in 2007 because the value of the underlying assets, especially housing, decreased faster.

The share of families carrying a credit card balance fell 6.7 percentage points to 39.4 percent in 2010. The median balance fell 16.1 percent to $2,600 in 2010 from $3,100 in 2007.

The proportion of families with debt payments greater than 40 percent of their income was nearly unchanged between 2007 and 2010.